Catamarans



March 1967 M. s. CHAPMAN 93 CATAMARANS Filed Oct. 18, 1965 29 33 30 L4 2/ /Z- I f 7' I INVENTOR. O MEEL //v s. CHAPMAN,

United States Patent M 3,307,511 CATAMARANS Merlin S. Chapman, RD. 4, Elm Grove, Wheeling, W. Va. 26003 Filed Oct. 18, 1965, Ser. No. 497,344 6 Claims. (Cl. 114-61) The present invention is directed to a catamaran type boat and is more particularly concerned with an improvement in hulls for such boats.

The principal object of the present invention is to provide a catamaran having keels for the hull thereof which will insure that the boat when being propelled through the water either by sail of when power driven and receives a side thrust that the outside of one hull thereof would tend to be lifted and the inside of the other hull would tend to dig into the water to provide a smoother riding boat which is faster and safer when making turns.

Another important object of the invention is to provide a catamaran having a pair of keels extending at about a 30 angle relative to the deck of the boat and also extending substantially the full length of the boat hull which would provide a stabilizing effect to the boat when being propelled through the water which efiect increases with the increase in speed of the boat.

Further objects of the invention will be in part obvious and in part pointed out in the following detailed description of the accompanying drawings, in which:

FIG. 1 is a side view of the lower portion of a catamaran according to the present invention with a hull portion broken away,

FIG. 2 is a bottom view of the present catamaran, and

FIG. 3 is a front view of FIG. 1 with the hulls shown in cross section.

Referring now more particularly to the accompanying drawings wherein like and corresponding parts are designated by similar reference character numerals 1 and 2 generally indicate similar longitudinally elongated and relative narrow hulls of the present catamaran.

Hull 1 has a flat top side 3, an outer side 4 curving inwardly towards the inner flat side 5 which extends normal to said top side. Flat bottom portion 6 connects outer side 4 with inner side 5.

A stringer 7 is embedded in outer side 4 at the corner formed thereby with top side 3 and extends the length of hull 1. A second stringer 8 is embedded in the corner formed by inner side 5 with said top side 3 and also extends the length of hull 1.

A plate 9 is embedded in outer side 4 in the lower portion thereof adjacent inner side 5 and is fixedly connected to hull 1 by conventional means such as screws and the like (not shown). Said plate 9 has a fiat cross sectional configuration and extends the length of hull 1. A plate 10 is fixedly connected to inner side 5 by conventional means such as screws and the like (not shown), has a flat cross sectional configuration and has its lower edge positioned against plate 9 to which it is connected by welding or the like. Plate 9 extends tangentially of outer side 4 on about a 30 angle to the top side 3 and thus on an obtuse angle to plate 10 and has an outer free marginal portion 11 extending beyond plate 10.

Hull 2 has a flat top side 12, a curving outer side 13 extending from said top side 12 towards a flat inner side 14 which in turn extends normal to said top side 12. A flat bottom 15 extends between and connects outer side 13 and inner side 14.

A stringer 16 is embedded in the corner of hull 2 formed by top side 12 and outer side 13 while a second stringer 17 is embedded in said hull in the corner formed by top side 12 and inner side 14. Said stringers 16 and 17 extends the length of hull 2.

A plate 18 having a flat cross sectional configuration is 3,307,511 Patented Mar. 7, 1967 embedded in outer side 13 and attached thereto by conventional means such as screws and the like (not shown), while a second plate 19 is joined to inner side 14 also by conventional means such as screws and the like (not shown) and also has a flat cross sectional configuration. Plate 18 extends on about a angle to top side 12 and thus on an obtuse angle to plate 19 with a free marginal portion 20 extending beyond plate 19. Said plate 19 has a lower edge positioned against plate 18 to which it is connected by welding and the like.

Hulls 1 and 2 are shown in FIG. 3 as for example of a solid material which can be a wood such as pine, mahogany, cypress, or balsa wood or it can be a floatable plastic such as styrofoam encased in a more rigid material. However, it is to be appreciated that hulls 1 and 2 can equally as well be of a conventional structure namely, having ribs and plankings or sheathing of wood, plastic or light weight metal such as aluminum.

A series of similar parallel and spaced apart cross pieces 21 are positioned on the top side 3 and 12 and stringers 7, 8, 16, and 17 are fastened thereto by screws, bolts and the like conventional means (not shown). Said cross pieces retain the hulls 1 and 2 spaced apart with plates 10 and 19 facing one another and preferably said plates are also parallel to one another, but may be curved if desired.

A deck 22 is fixedly mounted on cross pieces 21 and again connected thereto by conventional means such as screws, bolts and the like (not shown) while a mast 23 is mounted on said deck extending normal thereto and fastened to said deck by conventional means such as a socket or the like. The boom 24 is pivotally connected to mast 23 while a sail 25 which is partially shown in FIG. 1 is slidably connected to said mast and also attached to boom 24 in a conventional manner. Stay rope 26 which is partially shown is also connected to mast 23 at one end and to ring 27 at its opposite end for assisting in supporting said mast.

Uprights 28, 29, 32, and 33 are fixedly connected to said deck at the stern of the boat providing support for a back rail 34 and are supported by angle pieces 30 and 31 also fixedly connected to said deck as well as said rail by conventional means. A pair of ropes 36 extend from the opposite ends of rail 34 to a pair of uprights 35 at the bow of the boat providing a safety rail and upright 35 is fixedly connected to deck 22 by conventional means.

A motor 36' is supported on deck 22 and has a drive shaft 37 supported by bearings 39 and adjacent the stern of the boat with propeller 38 keyed to said shaft for being driven thereby.

In the use of the present catamaran, hulls 1 and 2 are floated upon the water and either or both the sail 25 or motor 36 used to propel said hulls longitudinally through the water and marginal portions 11 and 20 of the plates 9 and 18 respectively are submerged in the water and provide a pair of stabilizing keels. When the hulls 1 and 2 receive a side thrust, that is, either from the right or left of FIG. 3 such as when the wind strikes sail 25 or when the catamaran is turned by a pair of rudders 40 by a tiller 41 or when such turns are made when the boat is being propelled by a motor 36 and propeller 38, one keel will tend to ride up on the water and the other keel tends to dig into the water due to their slanting position. That is, if the thrust is from the right of FIG. 3 marginal portion 20 as well as the remainder of plate 18 will tend to ride upwardly on the water lifting hull 2 while the marginal portion 11 of plate 9 will tend to dig into the water as will plate 10 providing a breaking effect against the side thrust. On the other hand if the thrust is from the left of FIG. 3 plate 9 will tend to ride up On the water raising the hull 1 while marginal portion 20 of plate 18 and plate 19 will tend to dig into the water providing the breaking effect against the thrust from that side.

As a result the keels provided by marginal portions 11 and 20 the present catamaran will provide a smoother ride through the water than catamarans as heretofore known. Also this structure when riding through rough water will have a stabilizing elfect on the boat which increases as the propelled speed of the catamarans increases. Also such structure permits the catamaran to make turns when either under sail or motor faster and with less chance of over turning than previously known boats of this type.

The present invention is capable of considerable modifications and such changes thereto as come within the scope of the appended claims is deemed to be a part thereof.

I claim:

1. A catamaran comprising a pair of hulls positioned spaced apart, but extending longitudinally in a similar direction, means connecting and retaining said hulls in their relative positions, means for propelling said hulls through the water and connected thereto, each of said hulls being longitudinally elongated and having a relative narrow width with a top side and inner side joined by a curving outer side, a plate mounted on each hull curving outer side and extending beyond its hull inner side and said hull positioned with their inner sides facing one another.

2. A catamaran comprising a pair of similar hulls each elongated longitudinally and having a relatively narrow width, each of said hulls having a top side, a straight inner side extending normal to said top side and an outer side curving inwardly from said top side to said inner side, a pair of plates each joined to one of said hull outer sides adjacent the respective hull inner side and extending beyond its respective hull inner side, a second pair of plates each joined to one of said hull inner sides and extending against the one of said first mentioned plates on its respective hull, means extending between and connecting said hulls with their inner sides facing, but spaced apart and said first mentioned pair of plates extending in directions slanting toward one another and means for propelling said hulls longitudinally through the water.

3. A catamaran as claimed in claim 2 wherein said first pair of plates each have a flat cross-sectional configuration and extend tangentially of the hull outer side on which they are mounted.

4. A catamaran as claimed in claim 2 wherein said first pair of plates each extend longitudinally of the hull outer side on which they are mounted.

5. A catamaran as claimed in claim 2 wherein said second pair of plates each extend longitudinally of the hull inner side to which they are connected and both of said second pair of plates extend parallel to one another.

6. A hull for catamarans comprising an elongated, but relatively narrow hull having a top side, a fiat inner side and an outer side curving from said top side towards said inner side a plate imbedded in and joined to said hull side and extending beyond said hull inner and outer sides on an obtuse angle to said hull inner side.

No references cited.

MILTON BUCHLER, Primary Examiner.

ANDREW H. FARRELL, Assistant Examiner. 

1. A CATAMARAN COMPRISING A PAIR OF HULLS POSITIONED SPACED APART, BUT EXTENDING LONGITUDINALLY IN A SIMILAR DIRECTION, MEANS CONNECTING AND RETAINING SAID HULLS IN THEIR RELATIVE POSITIONS, MEANS FOR PROPELLING SAID HULLS THROUGH THE WATER AND CONNECTED THERETO, EACH OF SAID HULLS BEING LONGITUDINALLY ELONGATED AND HAVING A RELATIVE NARROW WIDTH WITH A TOP SIDE AND INNER SIDE JOINED BY A CURVING OUTER SIDE, A PLATE MOUNTED ON EACH HULL CURVING OUTER SIDE AND EXTENDING BEYOND ITS HULL INNER SIDE AND SAID HULL POSITIONED WITH THEIR INNER SIDES FACING ONE ANOTHER. 